The invention relates to a surface cleaning head for cleaning a surface, comprising a housing that has a cleaning chamber which is surrounded by a peripheral wall and open at the bottom, and in which at least one cleaning nozzle is mounted on a spray arm so as to be freely rotatable about an axis of rotation for applying cleaning fluid to the surface to be cleaned, and comprising a jet pump for suctioning off cleaning fluid that is applied to the surface, the jet pump having a pump inlet channel that is in flow connection with the cleaning chamber and is connected to a combining channel via a mixing chamber, a motive nozzle for forming a suction flow being situated upstream from the combining channel.
The invention further relates to a surface cleaning arrangement having a surface cleaning head and an outlet line.
This type of surface cleaning head is known from U.S. Pat. No. 4,895,179. A spray lance of a high-pressure cleaning appliance may be connected to the surface cleaning head so that the cleaning nozzle situated on the spray arm may be supplied with pressurized cleaning fluid by the high-pressure cleaning appliance. The cleaning fluid may be sprayed onto the surface to be cleaned by means of the cleaning nozzle. The nozzle thus experiences a recoil, thereby setting the spray arm in rotation about the axis of rotation. At least two diametrically opposite spray arms, each carrying a cleaning nozzle, are usually used, whereby the nozzles may be simultaneously acted on by pressurized cleaning fluid.
In addition to the cleaning nozzles, the known surface cleaning head has a jet pump which operates according to the principle of a Venturi pump. The jet pump is situated above the housing, and is in flow connection with the cleaning chamber via a connecting line leading alongside the cleaning chamber. The jet pump includes a pump inlet channel which is connected to a mixing chamber, and a combining channel downstream from the mixing chamber. Upstream from the combining channel, a motive nozzle is in alignment with the combining channel, and may be acted on by pressurized cleaning fluid so that a suction flow forms in the mixing chamber and the combining channel. A diffuser is connected to the combining channel. An outlet line may be connected to the diffuser. The suction flow generated by the motive nozzle allows the fluid that is applied to the surface to be cleaned, together with removed dirt, to be suctioned off and discharged via the outlet line.
For operating the surface cleaning head known from U.S. Pat. No. 4,895,179, the surface cleaning head is supplied with cleaning fluid under a pressure of at least 207 bar at a delivery rate of at least 1,620 liters per hour. Due to the high pressure of the cleaning fluid and the high delivery rate, a suction flow may be formed by means of the jet pump which is strong enough to effectively suction off the cleaning fluid that is applied to the surface to be cleaned.
Surface cleaning heads having at least one rotating cleaning nozzle which may be supplied with pressurized cleaning fluid and which have a jet pump for suctioning off the cleaning fluid that is applied to the surface are also known from DE 100 66 009 B4 and DE 103 13 396 B4. In these surface cleaning heads as well, the cleaning fluid is supplied to the motive nozzle under high pressure and at a high delivery rate.
It is an object of the present invention to improve a surface cleaning head of the generic kind in such a way that the pressure and the delivery rate of the cleaning fluid may be reduced without significant losses of suction force of the suction pump.